Enzymatic Electrochemical Production Systems
Electroenzymatic processes combine the high selectivity of enzymatic catalysts with the electrochemical regeneration of their co-factors (Figure EnzElectro). This is a promising conceptual approach for the development of new biotechnological processes [1,2]. In this context, the PSE group has investigated the synthesis of gluconic acid in a novel electroenzymatic reactor. Gluconic acid is an organic acid with applications in different industrial branches. It belongs to the commodities with an annual production of 60 kt. Gluconic acid can be obtained from the partial oxidation of glucose which is a renewable platform chemical. The current research in the PSE group is focused on the reactor level, where some important challenges in the field of electroenzymatic processes, like electrode performance and integration of enzymatic electrodes into the overall system were tackled. Typically enzymatic electrodes feature very low current densities in the μA cm-2range. By closely combining experiments  with mathematical modeling  PSE group was able to increase the electrode performance to mA cm-2range. The optimized enzymatic electrodes were integrated into a membraneless electroenzymatic reactor . Glucose conversion and selectivity were investigated using nuclear magnetic resonance spectroscopy (NMR) under different structural and operational conditions. Glucose conversions ranging from 56% up to 81% at related selectivity from 97% to 76% were achieved for different operational conditions. A space-time-yield of 18.2 mg h-1cm -2at 47% conversion was achieved, which is a significant improvement compared to the best published data [3 and references therein]. The long-term stability of the enzymatic electrodes was excellent .
 Vidaković-Koch, T. (2018). Electron transfer between enzymes and electrodes. In Advances in Biochemical Engineering and Biotechnology, pp. 1-47. Springer, Berlin, Heidelberg.
 Vidaković-Koch, T. (2017).Bio(electrochemical)systems for energy conversion and chemical production, Springer Handbook of Electrochemical Energy, pp 757-779, Springer, Berlin, Heidelberg
 Varničić, M., Vidaković-Koch, T. and Sundmacher, K. (2015) Gluconic acid synthesis in an electroenzymatic reactor. Electrochimica Acta, 174, 480-487.
 Do Thi, Q. N., Varničić, M., Flassig, R., Vidaković-Koch, T. and Sundmacher, K. (2015). Dynamic and steady state 1-D model of mediated electron transfer in a porous enzymatic electrode. Bioelectrochemistry, 106, 3–13.